81207331 has 2 divisors, whose sum is σ = 81207332. Its totient is φ = 81207330.

The previous prime is 81207281. The next prime is 81207353. The reversal of 81207331 is 13370218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81207331 - 2⁹ = 81206819 is a prime.

It is a super-2 number, since 2×81207331² = 13189261216287122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81207296 and 81207305.

It is not a weakly prime, because it can be changed into another prime (81207361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40603665 + 40603666.

It is an arithmetic number, because the mean of its divisors is an integer number (40603666).

Almost surely, 2^81207331 is an apocalyptic number.

81207331 is a deficient number, since it is larger than the sum of its proper divisors (1).

81207331 is an equidigital number, since it uses as much as digits as its factorization.

81207331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 81207331 is about 9011.5110275691. The cubic root of 81207331 is about 433.0437208172.

Adding to 81207331 its reverse (13370218), we get a palindrome (94577549).

It can be divided in two parts, 8120 and 7331, that added together give a palindrome (15451).

The spelling of 81207331 in words is "eighty-one million, two hundred seven thousand, three hundred thirty-one".